The Calvin Cycle
The steps of the Calvin cycle.
Terms in this set (8)
Step 1: Carbon Fixation
The enzyme rubisco combines CO2 with 5-carbon sugar rubulose biphosphate (RuBP). The unstable product formed splits into 2 molecules of 3-carbon 3-phosphoglyceric acid (3-PGA).
Step 2: Reduction
Energy from 6 molecules of ATP is used to oxidize NADPH to NADP+. Six molecules of 3-PGA are reduced, producing six molecules of energy-rich 3-carbon sugar G3P.
Step 3: Release of one molecule of G3P
Five of the previously created G3Ps remain in the cycle, but one molecule is released.
Step 4: Regeneration of RuBP
A series of chemical reactions uses energy from ATP to rearrange the atoms of the 5 G3P molecules, (15 total carbons), which forms 3 RuBP molecules (15 total carbons).
These will start another turn of the cycle.
Produced by Step 1
Six molecules of 3 Carbon 3-PGA
Produced by Step 2
Six molecules of 3 Carbon G3P
Result of Step 3
One G3P is released and five continue in the cycle
Produced by Step 4
Three molecules of 5 Carbon RuBP